2016/05/04

Be aware of RX issue when you use scheduler within Merge over GroupBy The following code snippets work well when no scheduler is used: Code Snippet var source = Observable.Return(1) .Concat(Observable.Never<int>()); var xs = from item in source group item by item % 3 == 0 into g from x in Observable.Merge( g.FirstOrDefaultAsync(), g.LastOrDefaultAsync()) select x; xs.Subscribe(Console.WriteLine); The code snippet will produce output of 1 When altering the code for better testability and adding scheduler to the Return and Merge operation, it will produce no output. ...